Water pipes are well known and come in a variety of forms, including hookahs and narghiles. The term “water pipe” will be used to encompass all such smoking devices, but the terms water pipe and hookah will both be used interchangeably for convenience in the description that follows.
The hookah or water pipe has been used for centuries to smoke both plain and flavored tobaccos, mixtures of various aromatic herbs and spices, or mixtures of both. Typically a hookah has a bowl in which tobacco is placed, the bowl being mounted on top of a reservoir structure. The interior of the reservoir is partially filled with water. Extending downward from the bowl into the reservoir is a tubular hollow stem, with its lowermost extremity immersed in the water. The interior portion of the reservoir structure (i.e., the air space) above the level of the water forms a chamber into which smoke may be collected. One or more flexible hoses extend outward from this smoke collection portion of the reservoir or from a neck base extending from and in fluid communication with the reservoir.
Inhaling through a flexible hose, a smoker causes smoke to be drawn from the bowl down the stem, passing the smoke through the water in the lower portion of the reservoir. Passing upwards through the water in the form of bubbles, smoke gradually fills the smoke collection portion of the reservoir, and when sufficient smoke has been collected, passes on through the flexible hose to the smoker. By drawing the smoke through a water reservoir, the smoke is filtered and cooled.
This basic functionality is shared by virtually all traditional hookahs, which generally differ only in size, shape, style and number of hoses, although the means used to burn the tobacco may also differ. Some use a lighted coal placed in or above the bowl with the tobacco to provide a heat source for burning the tobacco. Others may require an ignition source such as a match or butane lighter to be placed near the top of the bowl to begin burning the tobacco. However, all traditional hookahs use combustion as the method of producing smoke, thus also producing all the undesirable combustion by-products in the smoke. Use of water to filter and cool the smoke may reduce some of the undesirable smoke components, but some, such as carbon monoxide, heavy metal and potentially hazardous chemicals created by placing the aluminum foil that is used to cover the tobacco beneath the burning charcoal, cannot be removed in this manner.
Combustion has traditionally been the only technology available for production of smoke. However, electric power has allowed development of a variety of alternatives to combustion for use by smokers. These typically generate a sufficient amount of heat to vaporize volatile aromatic components of the tobacco without actually burning the tobacco, in this way avoiding production of undesirable combustion by-products such as carbon monoxide present in smoke. However, according to U.S. Pat. No. 7,287,530 to Stuart, despite the existence of these and other technologies, all hookahs and the vast majority of smoking appliances still rely on the use of combustion as the means to produce smoke for inhalation, and make no provision for the use of any alternate technology.